This invention relates generally to the field of telephone numbering systems, and particularly, discloses a simplified method of dialing in connection with telephone area code overlays and area codes in general, and an associated apparatus that enables individual telephone subscribers to utilize this simplified dialing method independently of the adoption or non-adoption of this method by the telephone companies and pertinent government agencies.
As population increases, and as the use of the telephone system grows to accommodate new, non-traditional uses of switched telephone connections such as facsimile transmission, internet traffic, and related non-voice, data applications, the existing 7-digit numbering scheme for local calling is coming under increased stress. Under the existing North American numbering plan, which addresses any given telephone location by (NXX)N23-4567, where N is a digit from 2 to 9, X is any digit from 0 to 9, NXX is an area code, and N23-4567 designates a 7-digit phone number with central office prefix N23, a single area code, in theory, can only accommodate up to 8 million numbers (1 million based on the last six digits, times 8, for a first digit between 2 and 9). This is further restricted, since any given central office prefix N23, which is addressed through a single central office, and which can accommodate up to ten thousand numbers, may be under-utilized, for example, in a rural area where a central office of given N23 prefix may only serve a few hundred or a few thousand telephones. With competition developing in local loops, the so-called xe2x80x9cCLECsxe2x80x9d (Competitive Local Exchange Carriers) are obtaining given N23 prefixes for their own central offices, exerting further pressure on our numbering supplies. The depletion of available numbers in an area code is called xe2x80x9cArea Code Exhaustxe2x80x9d. The process of replenishing the number supply in a numbering plan area is called xe2x80x9cArea Code Reliefxe2x80x9d.
Current solutions for Area Code Relief (splits and standard overlays) create, rather than solve, problems for customers. Recently, the widespread use of these methods has resulted in what can readily be described as a xe2x80x9cNational Area Code Disaster.xe2x80x9d Our dialing landscape has been damaged, and this damage has been expensive and disruptive for businesses and consumers. Some of the impacts from these current relief methods are outlined below.
FIGS. 1, 1A illustrate an established area code (818, as an example) before being impacted by area code relief. One solution which has been utilized, is so-called area code splitting, which is illustrated by FIGS. 2, 2A. In this solution, a geographic boundary is cut through the existing area code, the original area code (e.g. 818) is maintained on one side of the boundary, and a new area code (e.g., 626) is established on the other side of the boundary. This approach, however, is highly disruptive to telephone users both within and outside of the affected area code. Telephone owners in the new 626 area code effectively change to a new phone number overnight, and are forced to reprint letterheads, business cards, advertisements, directory listings, etc., in order to advise callers of their new area code. Callers both inside and outside the affected area code must adjust to the disrupted dialing patterns, including becoming familiar with the new numbers. Autodialers calling into the new area code, and from the new area code into the old area code, must be reprogrammed. Perhaps the only aspect of local calling which survives, is that callers within the old area code and the newly created area code can still use a 7-digit number to dial other telephones within their own area code""s boundaries. However, calls across the new border between the old area code and the new area code now require xe2x88x9210- or 1+10-digit dialing, and disruption occurs both within and outside of the pertinent area codes. Overall, area code splitting is cumbersome, disruptive, and expensive.
An area code split forces half of the customers in the affected area to give up their existing phone numbers, cuts abbreviated (7 digit) dialing areas in half, and permanently disrupts established dialing patterns both within the affected area and into the affected area from everywhere else in the world. The overall cost just for mopping up after a single area code split is estimated to be over 40 million dollars (this includes updating signs and stationary, reprogramming of burglar alarms, fire alarms and other auto dialing systems, notifying customers and friends of number changes, modifying local phone switches, etc.). This reshuffling of phone numbers creates confusion for customers, resulting in numerous missed or misdialed phone calls for many years to come.
Another solution, illustrated by FIGS. 3, 3A, is the standard overlay method. In this method, instead of the geographic split of FIGS. 2, 2A ,the new area code is xe2x80x9coverlaidxe2x80x9d on top of the original area code. The result is a form of xe2x80x9csubscription-based,xe2x80x9d rather than xe2x80x9cgeographicxe2x80x9d splitting. That is, once the original (or xe2x80x9cparentxe2x80x9d) 818 area code (for example) nears saturation, many new local telephone subscribers will be given numbers in the new (or xe2x80x9cchildxe2x80x9d) area code, such as 626 in this example. Over time, telephones with the 626 area code and telephones with the 818 area code will be intermingled throughout the geographic area described by the original 818 area code""s boundaries. A user who first subscribed to a telephone connection in the 818 area code before saturation (i.e., exhaust), and who subscribes after saturation, e.g., to a second telephone connection to run a facsimile machine, would possibly obtain a 626 number for the facsimile line, and thus could have lines with two different area codes under the same roof. Over time, the overlay area (i.e., that area served by both the parent (e.g. 818) and the child (e.g. 626) area codes) would have telephone numbers with both area codes interlaced throughout it, and a call across the street, or even within the same building, could well involve two (or more) area codes.
The advantage to this approach, is that nobody ever needs to xe2x80x9cchangexe2x80x9d their telephone number. Existing subscribers keep their original (the xe2x80x9cparentxe2x80x9d) area code, while new subscribers might obtain a number from the new (xe2x80x9cchildxe2x80x9d) area code. With this method, no one ever has to update advertising, letterhead etc., to inform customers and friends about the area code change, because only new subscribers would receive service in the new area code. In addition, this approach is transparent to people outside of the overlay area, whether receiving calls from, or dialing into, the overlay area. Thus, this overlay method is much less disruptive to existing subscribers than is the area code split of FIGS. 2, 2A.
The disadvantage of this method, is that it severely disrupts local dialing patterns. In particular, as illustrated, every call, even locally, now becomes a xe2x88x9210- or 1+10-digit call, in which the caller must supply an area code even for calls right across the street, or to the office upstairs in the same building. Thus, autodialers must be reprogrammed, directory listings must be reprinted with at least 10-digit numbers, small children or elderly or handicapped persons must learn or re-learn a more difficult dialing technique, and the simplicity of 7-digit dialing stands in peril of extinction. While the FCC mandate for dialing parity in overlays has been interpreted to require that xe2x88x9210- or 1+10 digit dialing be used for all overlay dialing, it would be desirable to achieve this required parity, if possible, by dialing fewer than xe2x88x9210- or 1+10 digits.
In summary, using standard overlays for relief also creates hardship for customers. Existing dialing patterns are disrupted for all customers in the affected area. Seven (7) digit abbreviated dialing is abandoned for less convenient (and very unpopular and controversial) xe2x88x9210- or 1+10 digit dialing. For all calls in a standard overlay scenario, the area code must be dialed before the 7 digit number, creating difficulty for customersxe2x80x94especially children, elderly, and handicapped. Many people have expressed concern that dialing multiple area codes for calls within a single geographic region will create a feeling of disunity for the area. The shift from 7 digit to xe2x88x9210- or 1+10 digit dialing also necessitates reprogramming for all burglar alarms, fire alarms and other automatic dialing systems which had previously been programmed with 7 digit numbers. Incomplete calls will occur when 7 digits are dialed without the area code, and it is likely that the wrong area code will often be used by mistake, which happens today even where area codes are not overlaid. And, the likelihood of misdialing at least one out of 10 or 11 digits is significantly greater than when only 7 digits are dialed (expect an increase of 42% for 10 digits and 57% for xe2x88x9210- or 1+10 digits).
By disrupting established dialing patterns, area code splits and standard overlays cause hardship, confusion and expense for customers, and prompt numerous misdials and wrong numbers.
It would be desirable if area code relief could be achieved with a minimum of disruption and expense. For a solution to be xe2x80x9cpreferredxe2x80x9d it would have to satisfy both the needs of the customer and the requirements of the telecommunications industry.
It would therefore be desirable to have a numbering plan which greatly reduces the confusion and inconvenience that is associated with having multiple area codes within individual neighborhoods and households.
It would further be desirable to have a plan which is non-disruptive to existing 7 digit and xe2x88x9210- or 1+10 digit dialing patterns, wherein no one is put in jeopardy by a change to their local dialing plan (especially children and elderly/handicapped persons), and existing auto dialers can complete calls without reprogramming.
It would further be desirable to have a plan which reduces the likelihood that the new overlay area code will be a stigma for new businesses.
It would further be desirable to have a plan which ensures that costs to businesses and disruption overall will be kept to a minimum.
For customers, a preferred solution would: be consumer friendly; allow customers to keep their existing area codes and phone numbers; preserve all dialing patterns to established phone numbers (backward compatibility); minimize impact on children and the elderly; avoid costly reprogramming of existing burglar alarms, fire alarms and other auto-dialers; save consumers, businesses and telephone companies money overall; and provide long term, non-disruptive relief to exhausted area codes.
For the telecommunications industry, a preferred solution must: offer benefit to customers; be competitively neutral; be technically workable; be cost effective to implement; be built on top of the existing network so that past investment is not discarded; and limit all costs and changes in xe2x80x9cdialing, switching and programmingxe2x80x9d to the geographic area in which the solution is implemented.
It would be difficult to argue against an alternative which met these specifications, yet it is natural that controversy might surround it.
The invention disclosed herein is based on the standard overlay method of FIGS. 3, 3A, but establishes a unified dialing plan for these overlays which eliminates the need for xe2x88x9210- or 1+10-digit dialing within an overlay region. It avoids the disruption of area code splitting as described above in connection with FIGS. 2, 2A, and it also avoids the need to dial xe2x88x9210- or 1+10-digit numbers within an overlay area as in FIGS. 3, 3A.
In particular, within an overlay area, the original (parent) area code is represented by a single-digit suffix xe2x80x9c0xe2x80x9d, and the child area code is represented by the single digit suffix xe2x80x9c1xe2x80x9d. Subsequent child area codes can be numbered 2 through 9, before the need arises to add a second digit to the suffix. For anyone within the overlay area (from either the parent or a child area code) who is dialing to a number in the parent area code, all that is required is to dial the original 7-digit local number, followed by the single-digit suffix xe2x80x9c0xe2x80x9d. In reference to FIG. 6, the xe2x80x9c0xe2x80x9d suffix causes computerized telephone number conversion device 1 (whether a central office switch 2, a custom calling service, or a customer premises equipment device 3, 4) to signal the seven digit number using the parent area code. Additionally, by default, if the first 7 digits are dialed and an eighth digit is not dialed before expiration of a predetermined timing delay, the device 1 will assume (by default) that the eighth digit is a zero, and the call will be routed to the seven digit number that was dialed, in the parent area code.
For anyone within the overlay area (from either the parent or a child area code) who is dialing to the (first) child area code, all that is required is to dial the original 7-digit local number, followed by the single-digit suffix xe2x80x9c1xe2x80x9d, which represents the (first) child area code. This suffix will cause the telephone number conversion device to signal the given 7-digit number, but in the (first) child area code. In short, using the earlier examples, a xe2x80x9c0xe2x80x9d suffix or a timing delay without a suffix causes the seven digits provided to be dialed into the 818 (parent) area code, while a xe2x80x9c1xe2x80x9d suffix causes the seven digits provided to be dialed into the 626 (first child) area code.
This system does not in any way affect or change the standard overlay method of FIGS. 3, 3A, but rather provides a simplified method for dialing within and between overlaid area codes. Full xe2x88x9210- or 1+10-digit dialing could still be used by someone wishing to do so, but simplified dialing using only 8 digits (or 7 digits with a timing delay for dialing to the parent area code) can likewise be used, since each seven-digit-plus-suffix combination can be mapped precisely into a corresponding xe2x88x9210- or 1+10-digit number. Ideally, this method would be implemented in central office switching equipment and would become adopted as a unified dialing plan.
Alternatively, or in supplement to this, this method can be implemented through customer premises equipment (CPE) that takes an 8-digit number (or a 7-digit number plus timing delay), and converts (maps) it into the appropriate xe2x88x9210- or 1+10-digit number (xe2x80x9c1xe2x80x9d+xe2x80x9c3 digit area codexe2x80x9d+xe2x80x9c7 digit telephone numberxe2x80x9d). The CPE would then send the xe2x88x9210- or 1+10-digits to the central office switch for signaling, while only requiring the caller to have dialed 7 or 8 digits to place the call.
In brief, the xe2x80x9cunified method and apparatus to simplify telephone area code dialingxe2x80x9d according to the invention comprises a dialing system which:
1) Allows for optional (not mandatory) xe2x88x9210- or 1+10 digit dialing within and between all area codes in the geographic overlay area;
2) Unifies all area codes in the geographic overlay area with a simple 8 digit (7+suffix) dialing system. The suffix represents one of ten possible overlaid area codes with xe2x80x980xe2x80x99 being the original area code, xe2x80x981xe2x80x99 being the first overlaid area code, xe2x80x982xe2x80x99 being a future second overlaid area code, etc. When the appropriate device (a switch, custom calling service or a computerized CPE device) receives the full 8 digits, it translates the number into a traditional 10 digit number (3 digit area code +7 digit phone number) and passes it through the network as if the number had been originally dialed as xe2x88x9210- or 1+10;
3) Preserves establishedxe2x80x987 digit stylexe2x80x99 dialing to all phone numbers in the original area code from any area code within the geographic overlay area, by use of a xe2x80x9ctiming delay.xe2x80x9d
Functionally the network switch, custom calling service or CPE will be looking for either xe2x88x9210- or 1+10 style numbers or 7+suffix style numbers. With default dialing, if only 7 digits are dialed, after an appropriate timing delay the switch will assume that xe2x80x980xe2x80x99 is the intended 8th digit and will put the call through to the original area code of the overlay area. In this way, backward compatibility is achieved for dialing to xe2x80x98pre-relief phone numbersxe2x80x99 from any area code in the geographic overlay area, and the system appears completely non-disruptive to the customer. In short, the invention offers an advanced 8 digit dialing system based on and fully compatible with overlay groupings, yet it is backward compatible with all established dialing patterns to existing (pre-relief) phone numbers.